Recognition, Compensation, and Prevention of Karoshi, or Death due to Overwork

Although it may not be a familiar term in the Western world, karoshi, or death due to overwork, represents a growing public health issue in eastern Asia.1 The term karoshi first appeared in Japan in late 1970,2 and since then, the proportion of individuals working excessive hours (>45 hours per week) has become significantly higher in Asia than in Western countries. The first reported case of karoshi occurred in 1969, and involved the death from stroke of a 29-year-old male worker in the shipping department of Japan's largest newspaper company.3 A culture of excessive work hours has since moved beyond Japan, alongside economic expansion, having now spread to other Asian countries, especially eastern Asia. According to an International Labour Organization report from 2014,4 for example, in 2013, 23% of ordinary Japanese employees worked 50 hours or more per week. The rate was 34% in Hong Kong and China, and 35% in South Korea, compared with 14% to 17% in Australia, New Zealand, and the United States, and less than 13% in nine other industrialized nations. There is, naturally, an increased concern regarding the potential impact of excessive working hours on the health of workers. In a recent meta-analysis of 25 studies with a total of 603,838 individuals, Kivimäki et al5 documented persuasive evidence that working long hours incurs a higher risk of stroke than working standard hours, although the association with coronary heart disease was weaker. Compared with standard working hours (35 to 40 hours per week), working long hours (≥55 hours per week) was associated with an increase in risk of incidence of 13% for coronary heart disease and 33% for stroke. Their article strongly supports other research describing a link between working long hours, and coronary heart disease and stroke. In Japan, long hours are defined as working more than 45 hours per month of overtime (or more than 51 hours per week overall). The standard classification for overwork in Japan is calculated monthly (rather than weekly), but is lower than in the recent study by Kivimäki et al.5 The first comprehensive program for the prevention of health impairment from overwork was launched by the Japanese Ministry of Health, Labour, and Welfare (MHLW) in 2002.6 It comprised three major focus areas as follows: reducing overtime work to 45 hours or less per month, introducing medical examinations for all workers, and offering consultations with doctors to provide health guidance for those who are overworked. During the past decade, however, compensated karoshi cases have increased steadily in Japan to around 300 to 400 per year in 2014.7 To some extent, this suggests that Japanese efforts have not yet been successful in reducing karoshi cases. There are various reasons why the Japanese program may not have worked as well as anticipated.8 First, it has been difficult to reduce excessive working hours in Japanese society because this behavior is often accepted as a normal aspect of working life. Second, the identification of karoshi risk factors other than long working hours and work environment aspects has been complicated. Issues relating to irregular working style, shift work, business practices, and lifestyle, for example, have not been sufficiently elucidated. Third, the general message regarding the detrimental effects of excessive work hours on health has probably still not been adequately heeded by the Japanese society. These issues have not gone unnoticed by policy makers, however, and the Japanese government has recently taken some significant steps toward the prevention of karoshi. In November 2014, the Basic Act to Accelerate Moves for the Prevention of Karoshi was created to encourage a society where people can be free from death due to overwork and can continue to work productively in good health, with a reasonable work-life balance.8 The 2014 Act defines karoshi as any of the following (translated from Japanese): Death from cerebrovascular or ischemic heart disease due to excessive workload; or Suicide caused by a mental disorder due to severe stress at work; or Cerebrovascular or ischemic heart disease due to excessive workload or a mental disorder due to severe stress at work (defined by the onset of a condition and not necessarily leading to a fatality). The 2014 Act obliges inquiries into work-related deaths and illness, as well as moves to accelerate their prevention, such as dissemination and awareness raising, survey and research activities, and annual reporting of the progress to the Japanese Diet. While the government, employers, and individuals must all cooperate with the Act, at present, there are no penalties for noncompliance. Although the clearest karoshi risk factor is long working hours, it is also important to remain mindful of other potential contributors. Various work-related risk factors (eg, shift work, chemical exposure, and psychological distress) are also known to be associated with cerebrovascular or ischemic heart disease.9–11 In the diagnostic guidelines for occupational cardiovascular disease in Japan,12 after considering working hours, doctors are also expected to consider working patterns (eg, irregular working style, long contract hours, frequent business trips, and shift work), work environment (eg, extremes of temperature, noise and time differences), as well as severe psychological distress. The guidelines outline some specific events that may cause severe psychological distress (eg, severe diseases and injuries due to work-related accidents or disasters, causing severe accidents or disasters that lead to death and/or injury, and compelling a worker to retire for some reason) and overtime work (working more than 100 hours overtime per month). At present, Japan, Korea, and Taiwan are the only countries that specifically identify cardiovascular and cerebrovascular disease due to heavy workloads as occupational diseases.13 Diagnostic guidelines in Japan and Taiwan, but not Korea, now include working hours as a major risk factor. As global interest in cardiovascular disease risk factors increases, other countries may now recognize long working hours as a key problem to be addressed. To help identify, address, and ultimately prevent karoshi, governments around the world should therefore work toward creating appropriate occupational health frameworks and protocols, by drawing on over four decades of experience in Japan.